1. Field of the Invention
The present invention relates to a revolution control circuit for internal combustion engines, particularly Diesel engines, whereby when the speed of a Diesel engine exceeds its normal maximum revolutions, a control element such as the control rack of a fuel injection pump controlled by a pneumatic governor or a throttle valve for regulating the pressure in an intake manifold is forcibly actuated to reduce the quantity of fuel delivered by a fuel injection pump with a pneumatic governor and thereby to prevent the Diesel engine from operating at an excessive speed.
2. Description of the Prior Art
Heretofore known Diesel engine of the type equipped with a fuel injection pump having a pneumatic governor have a disadvantage in that if the control characteristic of the pneumatic governor changes due to variation of the atmospheric pressure, for example, the Diesel engine tends to operate at an excessive speed which causes damage to the engine.